Hinged track



Dec. 12,1967 R R DS ET AL 3,357,750

HINGED TRACK Filed Oct. 6, 1965 5 Sheets-Sheet 1 F'Il3 q INVENTORS RALPH K. REYNOLDS DAVID L.WHITAKER ATTORNEY Dec. 12, 1967 R. K. REYNOLDS 3,357,750

HINGE!) TRACK Filed Oct. 6, 1965 5 Sheets-Sheet 2 P'Il3..2

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INVENTORS RALPH K. REYNOLDS DAVID L.WHITAKER ATI'ORNEY Dec. 12, 1967 R. K. REYNOLDS ET AL 3,357,750

HINGED TRACK Filed 001;. 6, 1965 5 Sheets-Sheet 5 INVENTORS RALPH K. REYNOLDS DAVID L.WH|TAKER F nYm/m wlq.

ATTORNEY Dec. 12, 1967 REYNOLDS ET AL 3,357,750

HINGED TRACK Filed Oct. 6, 1965 5 Sheets-Sheet 1 LA a g T'I [3 1 1 I i gl g mvsmons Vi RALPH K.REYNOLDS DAVID L.WH|TAKER BY MW: a ATTORNEY D66. 12, 1967 R, K REYNOLDS ET AL 3,357,750

HINGED TRACK 5 Sheets-Sheet 5 Filed Oct. 6, 1965 IF'IE'| E 10 lOHO n4 1 IE" I[3 l [II mvsmons RALPH nnzmmos oawmwurmnsn BY kz w A'I'I'ORNEY United States Patent 3,357,750 HINGED TRACK Ralph K. Reynolds, Saratoga, and David L. Whitaker, San Jose, Calif., assignors to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Oct. 6, 1965, Ser. No. 493,432 8 Claims. (Cl. SOS-11) ABSTRACT OF THE DISCLOSURE Permanently assembled leaf hinge units are coupled together to form an endless crawler track chain. The same coupling means secure track shoes to the chain so that the intermediate one of any three adjacent hinge units can be removed and replaced, without destroying the continuity of the track, by disconnecting the confronting leaves of the two hingles spaced longitudinally of the track to release the intermediate hinge. By performing this operation twice for the hinges aligned transversely of the track, any track shoe link can also be replaced without destroying the continuity of the track. In one species of hinge, the drive sprocket engagement is with apertured leaves of the hinge.

This invention relates to improvements in crawler treads and more particularly to built-up crawler treads.

In the interest of economy, reliability and ease of maintenance earlier track designs were constructed of one or more flexible chains having track shoes rigidly fastened by rivets, bolts, or keys to the links of the chain. This design is usually referred to as the built-up type. Its simplicity recommended this design for wide spread military and non-military uses but experience with such designs brought to fore a weakness rendering this design limited in its application. The problem encountered was the loss of the track shoes due to shearing of the fasteners. A representative example of this construction is shown in United States Patent 1,536,604 dated May 5, 1925.

The built-up or chain-type track has been displaced by the link type track since this construction is considerably stronger. In the link type track each of the ground engaging plates are formed with lugs through which extend pivot pins to form a continuous flexible belt. The main problem encountered with this type of track concerns the wearing and retention of the pivot pins and the fact that field replacements of worn track shoes are rather ditlicult and require tools especially adapted for this purpose.

In an effort to reduce the wear of the pivot connections caused by the infiltration of dirt, lubricated crawler tracks have been proposed but due to the expense and difficulty in replacing worn parts, this design does not lend itself to be practical for certain military and non-military uses. A widely used method of reducing wear has been the incorporation of rubber bushed pin connections. The bore of the lugs and the diameter of the pin are sized to define an annular space within which the rubber bushings are located. The unrestrained diameter of these rubber bushings are substantially greater than the diameter of the lugs so that upon assembly the rubber bushing is extruded and held under compression completely filling the annular space. Under these conditions the relative pivotal movement between adjacent links of the track subject the rubber bushing to shearing forces.

When a rubber bushed track is assembled, adjacent links are oriented to define a predetermined angle which will maximize the torsional fatigue life of the rubber bushings. This predetermined angle is normally midway between the limits of angular oscillation between adjacent track shoes during vehicle operation.

When it is required to replace a track shoe in a rubber bushed crawler tread, special tools are required to remove the rubber bushed pins and it is necessary to orient the replacement shoe at a definite angle prior to insertion of the pivot pin and the rubber bushing. It often happens, especially in field replacement, that the required orientation is not performed properly thereby possibly subjecting the rubber bushing to twice the value of shear it is designed to withstand. This causes rapid failure of the bushing.

The present invention discloses a rubber bushed hinged connection which avoids the expense, reduces the time, and avoids the possibility of incorrectly assembling the rubber bushing. This invention also obviates the need of special tools for repairing the track.

Accordingly, it is one object of this invention to interconnect the shoes of the crawler track so that individual treads or hinges may be separately replaced without re moving the hinge pin between the adjacent shoes.

Another object of this invention is to provide a crawler tread that can be assembled and disassembled by ordinary readily available tools.

Another object of this invention is to provide a crawler track which may be disassembled at any pitch without disassembling the hinge unit itself.

Another object of this invention is to provide a built-up crawler track wherein the strength of the chain is not affected by the strength of the ground engaging shoe.

These and other objects and advantages of the present invention will be apparent in the following description and the accompanying drawings in which:

FIGURE 1 is a perspective of the hinge connection constructed according to the invention.

FIGURE 2 is a top plan of FIGURE 1.

FIGURE 3 is a transverse section taken substantially along the offset cutting plane 33 of FIGURE 2.

FIGURE 4 is an axial section of the hinge unit taken substantially along the line 44 of FIGURE 2.

FIGURE 5 is a plan view of a modified form of a hinge unit incorporating the invention.

FIGURE 6 is a transverse section taken along the offset cutting plane 66 of FIGURE 5.

FIGURE 7 is a plan of another modified form of hinge unit constructed according to this invention.

FIGURE 8 is a section taken along the offset cutting plane 8-8 of FIGURE 7.

FIGURE 9 is a plan view of still another modification of the hinge unit constructed according to this invention.

- FIGURE 10 is a section taken substantially along the offset cutting plane 1010 of FIGURE 9.

FIGURE 11 is a section of a modified form of the hinge connection which may be utilized in the modification of FIGURE 7.

Referring now to FIGURE 1 there is shown a portion of the crawler track constructed according to this invention and it is generally indicated by the numeral 10. Each pitch of the track comprises an inverted generally U- shaped rigid plate 12 to which is secured, by a bolt 14,

'a ground engaging rubber block 16. At the transverse center of each plate an upwardly extending generally pyramidal guide horn 18 is provided which serves to maintain the track in a predetermined orbital plane. On each plate 12, and on opposite sides of the guide horn 18, hinge assemblies 20, preferably of the type referred to as a l-2 linkage, are rigidly and detachably mounted to the upper surface of each rigid plate 12. Since the illustrated hinge assemblies are symmetrical, only that hinge assembly appearing on the right hand side of FIG- URE 1 will be described in detail.

The illustrated hinge assemblies 20 are preferably cast parts and are detachably rigidly connected to the plates 12. Referring to FIGURE 1 it will be seen that each hinge assembly comprises three members which are permanently pinned together preferably by a rubber bushed pin prior to their attachment to the plates 12. As shown in FIGURE 1, each hinge assembly comprises a central elongate leaf 22 having a bored male lug 24 for receiving a rubber hushed connecting pin. The central portion of the leaf overlying the plate 12 is provided with a pair of laterally spaced upwardly extending parallel ribs 26 interconnected at respective ends by an integral wall 28. These ribs and the wall form a generally rectangular opening for receiving the teeth of the driving sprocket to thereby effect orbital movement of the crawler chain. Each central leaf also includes lateral extension 30 forming platforms upon which are mounted the remaining portions of each hinge assembly as will be presently described. The hinge assembly also includes leaf members 32 and 34 formed with lug portions '36 which are spaced apart a sufiicient distance to receive therebetween the male lug 24 of the central leaf 22. A tubular pin 38 and rubber bushings 40 are inserted through the lugs thereby pivotally interconnecting the hinge members 22, 32 and 34. The pivotal connection is shown best in FIGURE 4.

The leaves 32 which are located closest to the lateral edges of the plate '12 have a lower wall portion 42 overlying the lateral extensions 30 of the central leaf 22 and upwardly extending strengthening ribs 44. A pair of bolts 46 extending through holes formed in the rigid plate 12, through the lateral extensions 30, and the lower wall 42 rigidly attached to the leaf 32 of one hinge assembly to the leaf 22 of an adjacent hinge assembly.

In addition to providing interconnection of adjacent hinge assemblies, the leaf members 34 are formed with a cavity surrounded by a narrow wall 50. A rubber block 52 of suitable shape is fixed within a cavity by any conventional method such as bonding. The rubber block is formed with a flat upper surface which is engaged by the bogie wheels of the vehicle. This surface is generally known as the wheel path or guiding surface. Each of the leaf members 34 overlies the inner lateral extension 30 of the central leaf 22 and are attached to the plate 12 by conventional nut and bolt assemblies 54.

In accordance with one important aspect of this invention, the respective leaves of each hinge assembly are pivotally interconnected by the pin 38 and a rubber bushing 40 prior to their attachment to the plates 12. During the assembly, the leaf members 32 and '34 are held in a common plane and the leaf member 22 is located in a plane which defines an angle with the plane containing the leaf members 32 and 34. The angle between such planes is an engineering design consideration depending upon the amount of shear that the rubber bushing 40 is designed to withstand. When the leaf members are disposed at an angle relative to each other, the pin 38 and the rubber bushing 40 are inserted into the lugs 36 and 24 and they assume the position shown in FIGURE 4. Prior to being assembled the rubber bushings 40 have a free diameter which is substantially greater than the diameter of the lugs 36 and 40. Upon assembly they are extruded, subjecting the bushings to a rather large compressive force.

According to the above described construction it should be readily apparent that by providing preassembled hinge assemblies which are detachably connected to the longitudinally adjacent track shoes, replacement of any desired hinge assembly or any track shoe is easily performed since all that is necessary is to remove the various bolts connecting the hinge assemblies to the track shoes.

FIGURES and 6 show a modified version of the hinge assembly incorporating the principles of this invention and it is generally indicated by the numeral 56. The hinge assemblies are arranged to be independently connected to adjacent track shoes so that each individual hinge may be attached and removed without disturbing the fasteners of an adjacent hinge.

This embodiment comprises rigid laterally extending channel members 60 having centrally located upwardly extending guide horns 62. On either side of each guide horn, suitable rubber pads 64 are provided which are rollingly engaged by bogie wheels. The hinge assembly includes a central leaf 66 secured to one of the channel members 60 by the bolts 68 and leaves 70 are secured by bolts 72 to an adjacent one of the channel members 60. A tubular pin 74 and a rubber bushing 76 extending through the lug portions of each leaf pivotally interconnect these leaves together and they assume the relationship shown in FIGURE 5. The leaves 70 are spaced a sufficient distance apart to receive therebetween the leaves 66 of an adjacent hinge assembly.

By virtue of this constructon any one of the hinge assemblies may be easily removed or attached to adjacent track elements by simply removing the bolts 68 and 72 while the fasteners holding the adjacent hinges to the track shoes are not disturbed. The hinge assemblies of this embodiment are also assembled priot to their being attached to the track shoes in order to assure proper stressing of the rubber bushing.

Yet another embodiment of this invention is shown in FIGURES 7 and 8. Although this embodiment discloses a hinge assembly which can be attached to the track shoes in its assembled relationship, it has the added advantage of providing for pivot pin seals, if desired. This embodiment includes a suitable channel shaped track shoe 78, adjacent pairs of which are interconnected in spaced relationship by hinge assemblies 80. Each hinge assembly comprises a central, generally rectangular leaf portion 82 having a tubular lug 84 formed on one end thereof. A preferably solid pin 86 and a rubber bushing 88 are assembled within a lug portion 84 and the pin is of sutlicient length to extend beyond the lateral sides of the leaf 82. Leaf portions 90 are formed with bored lugs 92 and are press-fitted on the outwardly laterally extending portions of the pin 86.

In the event a track of the lubricated type is desired, the rubber bushing 88 may be eliminated and the bore of the lug 84 would then be appropriately sized to allow free rotation of the pin 86 relative to the leaf members.

Before leaf portions in 90 are press fitted on the pin 86, a suitable seal 94 whether it be of elastomeric material, Teflon or rubber-backed rotary metal seals is fitted in suitable recesses formed in the tubular l-ug 84. Each leaf member 90 is formed with inwardly extending ears 96 which underlie the leaf portion 82 of a longitudinally adjacent hinge assembly. Bolt and nut assemblies 98 extending through suitable bores formed in the track shoes 78, the ears 96, and the leaf portion 82 rigidly interconnect the hinge assemblies to the track shoes.

The significant feature of the embodiment shown in FIGURES 7 and 8 pertains to the fact that this type of hinge assembly is well adapted for a rubber hushed track or a lubricated track and in either case replacement of the shoes or the hinge assemblies is easily accomplished by merely removing the appropriate nut and bolt assemblies.

FIGURE 11 shows a modified form of a hinge pin connection which can be used with a two leaf hinge of the type shown in FIGURES 7 and 8, the main difference being that the leaf members 90 are made as one leaf. The hinge connection illustrated in FIGURE 11 comprises a metal bushing 91 and a rubber bushing 88a which is secured by bonding, or any other suitable method, to the exterior surface of the metal bushing. These bushings are forcibly fitted in the bore of the lug 84. The leaf 90 is positioned so that the bore of the lugs 92 are in alignment with the bushing 91 and the pin 86a is then press-fitted through the lugs 92 and the bushing 91 pivotally rigidly attaching the leaf members together.

The relative pivotal movement between the leaves 90 and 82 stresses the rubber bushing 91 as in the prior modifications. In this modification, however, assembly of the cooperating leaf members avoids the possibility of misalignment of the bolt holes thus avoiding operator error and avoiding the necessity of providing special assembly fixtures for positioning the leaf portion 90 of FIGURES 7 and 8. The pin connection of FIGURE 11, however is not practically adapted to provide lubricated pin joints.

The embodiment of the invention shown in FIGURES 9 and 10 illustrates a very compact structure of a hinge assembly which merely includes two parts interconnected by a rubber hushed pin. This hinge assembly generally indicated by the numeral 100 includes one leaf portion 102 formed preferably with tapering side walls 104 and a central recess 106 in which is located the leaf member 108 of an adjacent hinge assembly. Axially spaced lug portions 110 are provided for receiving a pivot pin 112 and a rubber bushing 114. The leaf member 108 is also formed with a lug portion 116 being of sufiicient width to be received between the lug portions 110. The lug 116 is also bored to receive the pivot pin 112 and the rubber bushing 114. As shown in FIGURE 10 the leaf portion 108 overlies the leaf portion 102 and they are fastened to a track shoe 118 by a pair of nut and bolt assemblies 120. It will beobvious that this embodiment also incorporates those structural features which will permit replacement of any hinge unit at any point in the crawler track and yet insure that the torsional loads applied to the rubber bushing will not exceed the design limits.

Although several embodiments incorporating the principles of this invention have been shown and described, it will be understood that the apparatus is capable of variations without departing from the principles of the invention, and that the scope of the invention should be limited only by the scope and proper interpretation of the claims appended hereto.

Having thus described our invention, what we claim as new and desire to protect by Letters Patent is:

1. A hinge connection for pivotally interconnecting adjacent shoes of a crawler track so that the individual shoes or the hinges may be separately replaced without removing the hinge pin, said hinge comprising spaced apart generally parallel hinge leaves removably rigidly securable to one track shoe and having respective overhanging pin-receiving portions, a single hinge leaf located between said spaced apart leaves and removably rigidly securable to longitudinally adjacent track shoe, said single leaf having a portion overhanging its associated.

shoe and also having a pin-receiving portion, and a pivot pin including a rubber bushing permanently seated in the overhanging portion of said leaves, said spaced apart leaves being spaced a sufiicient distance apart to receive therebetween the single hinge leaf associated with another longitudinally adjacent hinge connection.

2. A hinge connection for a crawler track comprising, a pair of spaced apart leaves having respective portions formed to receive a pivot pin, another leaf located between said pair of leaves and also having a portion formed to receive a pivot pin, a pivot pin extending through said portions pivotally connecting all of said leaves, said another leaf including a central upstanding projection having an opening therein engageable by the teeth of a driving sprocket and lateral extensions located on opposite sides and at the base of said projection, means detachably securing the pivotally connected leaves to adjacent ground engaging shoes of the crawler track, said leaves being associated so that one pair of spaced apart leaves of one hinge connection overlie the lateral extensions of the adjacent hinge connection.

3. A crawler chain segment comprising a plurality of ground engaging track shoes, a permanently preassembled leaf hinge structure for pivotally interconnecting each pair of said shoes, said hinge including at least two leaves having aligned apertured lugs, a pivot pin extending through said lugs, one of said leaves being aligned with one of said pair of track shoes and provided with a laterally directed extension in contact with a first adjacent hinge structure leaf overlying the same track shoe, attachment means for securing the thus contacting hinge portions together and to the track shoe aligned therewith, the other of said leaves of said first mentioned hinge overlying the other track shoe of said pair of track shoes and contacting the laterally directed extension of a second adjacent hinge, and attachment means for securing said other of said leaves and said extension of said second adjacent hinge to said other track shoe.

4. A crawler chain assembly comprising a plurality of ground engaging track shoes, a plurality of preassembled leaf hinges for individually pivotally interconnecting each adjacent pair of said track shoes, each hinge including at least two leaves coupled by a pivot pin, each leaf of each said hinge being superimposed on a leaf of an adjacent hinge, common attachment means securing one of the leaves of a hinge to one of said track shoes and to one leaf of a first adjacent hinge, and common attachment means securing the other leaf of said first mentioned hinge to the next adjacent track shoe and to a leaf of a second adjacent hinge.

5. The invention of claim 4 wherein each of said hinges has a leaf thereof formed to engage the teeth ofa driving sprocket.

6. The invention of claim 4 wherein selected hinge leaves of said hinges include pads which cooperatively define a guiding surface for a crawler chain guide wheel.

7. The invention of claim 4 wherein said leaves of each preassembled hinge are spaced along the axis of said pivot pin, and wherein one leaf is provided with a laterally directed extension to which the leaf of an adjacent hinge is connected by said common attachment means.

8. The invention of claim 4 wherein each of said plurality of preassembled leaf hinges comprises a central leaf and two separate side leaves having lug portions mounted with a press fit on said pivot pins, said side leaves being laterally spaced apart and located one on each side of said central leaf, removable means securing said central leaf to one of said track shoes, common removable means securing said side leaves to the next adjacent one of said track shoes, and annular face seals circumscribing said pivot pin, each seal being arranged to prevent the intrusion of foreign matter between the lug portions of said central leaf and said side leaves.

References Cited UNITED STATES PATENTS 1,913,098 6/1933 Alden 30542 2,391,524 12/1945 sorensen 305-42 2,563,848 8/1951 Knox 305-54 2,731,304 1/1956 Kubaugh 305-51 X 3,092,423 6/1963 Speidel 30558 X FOREIGN PATENTS 811,550 8/1951 Germany 539,936 9/1941 Great Britain.

RICHARD J. JOHNSON, Primary Examiner. BENJAMIN HERSH, Examiner. 

4. A CRAWLER CHAIN ASSEMBLY COMPRISING A PLURLITY OF GROUND ENGAGING TRACK SHOES, A PLURALITY OF PREASSEMBLED LEAF HINGES FOR INDIVIDUALLY PIVOTALLY INTERCONNECTING EACH ADJACENT PAIR OF SAID TRACK SHOES, EACH HINGE INCLUDING AT LEAST TWO LEAVES COUPLED BY A PIVOT PIN, EACH LEAD OF EACH SAID HINGE BEING SUPERIMPOSED ON A LEAF OF AN ADJACENT HINGE, COMMON ATTACHMENT MEANS SECURING ONE OF THE LEAVES OF A HINGE TO ONE OF SAID TRACK SHOES AND TO ONE LEAD OF A FIRST ADJACENT HINGE, AND COMMON ATTACHMENT MEANS SECURING THE OTHER LEAD OF SAID FIRST MENTIONED HINGE TO THE NEXT ADJACENT TRACK SHOE AND TO A LEAF OF A SECOND ADJACENT HINGE. 